Sheri ....
Tarev is right on about plants abandoning growth they cannot support during high temps.
I live in a climate very similar to his, but I live further north and up in the mountains above the Valley, so there is a greater variance between my day temps and night temps. I also don't get the benefit of the Delta breezes he has mentioned in other posts.
I grow a lot of roses, which I normally prune in spring, but I do need to prune some of them a bit in fall to avoid snow breakage. My rule of thumb is not to prune a plant back until the day temps are in the 80s and are likely to stay there or go lower. This is because in many plants, certainly roses, pruning stimulates new growth which would fry when temps are in the 90s or above. This uses plant energy, so I wait.
I also don't do a hard prune in fall because my modern roses store nutrients in their canes to carry them through the winter months and into spring. My pruning is simply to open the plants up so that the snow can fall through them and so that I am the one deciding how far the plant gets pruned back rather than Mother Nature.
I, too, like getting that last flush of roses ..
I don't know your climate, but I thought I'd share a different approach to pruning.
Smiles,
Lyn
